The modern farm practice of applying chemicals to the soil to obtain an optimal crop yield has been used for many many years. The farmer, as always, desires sufficient soil fertility to ensure that a successful harvest will result from his planting. Cropland productivity is increased considerably with the application of specific chemicals such as nitrogen, phosphorous and potassium. These fertilizers are applied by diverse types of field equipment and a decision must be made as when to apply, how much to apply, the nutrient requirements of the particular plants he wants to grow, the field conditions and climatic conditions. In the case of nitrogen, local field conditions determine the quantity of ammonium held, on the exchange complex of the soil, and the precise mechanics of conversion to more available forms via bacterial reaction. After the transformation of ammonium by soil bacteria to nitrate it becomes very mobile due to its solubility with soil water and therefore the topography of the land can be very important. To address the problem of these varying levels of the nitrogen requirement a producer will normally have representative soil samples taken from a field, have them tested and determine how much fertilizer is required to bring the field to a desired level. In most cases it is found that the low areas have a high residual count, the midslopes a medium count and the higher areas a low count. In view of the high cost of time and fertilizer and the fact that there is a drastic diminishing yield response after a certain level of fertilizer application, the producer must act accordingly.
In order to alleviate the above mentioned problem of waste of time and money, attempts have been made for optimum production. The three most closely related patents known to applicant are U.S. Pat. Nos. 5,033,397, 4,193,356 and Canadian patent 1,178,852.
The U.S. Pat. No "397" teaches a plurality of ground-engaging tools in association with individual soil sensors which measure soil chemical levels. The appropriate concentration is found and an automatic servo-controlled delivery system applies the appropriate amount of fertilizer, substantially in the location from which the soil measurements were taken. While this solution to the problem appears to be desirable the cost for the average producer would be prohibitive. Applicants device also provides an "on the go" method of a variable application of fertilizer with the operator varying the rate according to prior laboratory tests taken at various location in the field.
The U.S. Pat. No. "356" teaches a monitoring of a decrease of the amount of a fluid being applied to the soil by a nozzle malfunction and really has nothing to do with a controlled increase or decrease of the total quantity of fluid applied.
The Canadian patent "852" deals with controlled experiments where the composition of the mixture can be controlled and where the outflow to each nozzle is controlled. The control of the mix being possibly adjusted by remote control from the drivers cabin. Applicants invention is directed to a remotely controlled metering device which is controlled "on the go" by the operator who interprets a calibrated read out of the quantity of fertilizer being applied to the soil.
In summary applicant has provided a device for a practical, efficient and economical "on the go" multirange application of a fluid fertilizer to the soil for optimum crop production.